A novel fully integrated dynamic thermal management circuit for system-on-chip design is proposed and will be implemented in a VLSI device. Instead of worst-case thermal management used in conventional systems, this design yields continual monitoring of thermal activity and reacts to specified conditions. With the above system, we are able to incorporate on-chip powerlspeed modulation and an integrated multi-stage fan controller, which allows us to achieve nominal power dissipation and ensure operation within specification. Both architecture and circuitry are optimized for modem system-on-chip designs. This design yields intricate control and optimal management with little system overhead and minimum hardware requirements, as well as provides the flexibility to support different management algorithms. This circuit will be fabricated in a TSMC 0.25μm process through MOSIS.